The distribution of various packages of goods for the warehouse and distribution market, such as dry grocery market, generally involves high numbers of product (SKU's) that correspond to many unique sized products. Typically, an industry customer can have over 15,000 SKU's. A flexible end of arm tool is desired for distribution of all sized product.
End of an tools (EOAT's) are used in conjunction with robot arms for transporting packaged goods to and from pallets. EOAT's, therefore, must be adaptable to different sizes and shapes of packaging. Common EOAT's provide either servo driven or pneumatic fork/rail type tools with or without top clamping features, or a servo driven or pneumatic pusher with fixed fork/rail underneath support type end of arm tooling with or without clamping features.
The servo-driven or pneumatic fork/rail/platform type end of arm tool takes advantage of underneath extendable/retractable support forks or rails or platform (hereinafter referred as forks/rails/platform) that provides the product support function of the end of arm tool. This known EOAT typically has a top pad or clamp, or even an array of vacuum cups, that descends to capture the product between the top pad/clamp and the underneath extendable/retractable support forks/rails/platform. The tool releases the product by lifting the top pad/clamp and withdrawing or retracting the forks/rails/platform from underneath the product.
The fixed fork/rail with servo-driven or pneumatic pusher type end of arm tool takes advantage of underneath fixed support forks/rails/platform that provides the product support function of the end of arm tool. The tool typically has a top pad or clamp that descends to capture the product between the top pad/clamp and the underneath fixed support forks/rails/platform. The tool releases the product by lifting the top pad/clamp and pushing the product off of the forks/rails/platform via a pusher arm.
A disadvantage of these prior art EOAT's is that both the underneath rails and top pad/clamp are typically sized two ways. The first method is sizing for the largest product, there are a number of forks/rails/platform that are spread-out underneath the product to allow for stable carrying of the product to be handled, forcing the EOAT to be large and having excess forks/rails/platform providing out the sides of smaller products (product sizes that are less than the largest product size) being handled with the same tool. Sometimes the forks/rails can be withdrawn individually, but still cause side-to-side restrictions at the rear end of the tool when the product is handled where the withdrawn forks/rails/platform are retracted out of the back of the tool, causing restrictions to adjacent product. This restriction is typically experienced when product is being placed next to other product during the building of a layer of products, preventing product to product placement.
Additionally, the use of a large pad/clamp to secure the product between the pad/clamp and the underneath support forks/rails/platform causes the end of arm tool to be large and have excess pad/clamp surface protruding out the sides of smaller products (product sizes that are less than the largest product size) being handled with the same tool. This prevents product from being placed next to other product.
The second method is sizing for the smallest product, where there are fewer forks/rails/platform, and therefore a narrower platform, the rails are spread-out underneath the product to allow a smaller overall width. This reduces or eliminates the side-to-side restriction when placing product next to other product. However, this prevents the tool from handling large product, where out-board product support is required to handle the product reliably.
Additionally, where there is a small pad/clamp to secure the product between the pad/clamp and the underneath support forks/rails/platform, this also prevents the end of arm tool from securely capturing or clamping larger product during handling, risking that the product is dropped during handling.
U.S. Pat. No. 7,153,085 teaches a multi-modal package handling tool including vacuum carrying units and extendable package grippers.
U.S. Pat. No. 4,976,484 teaches an adjustable work positioning device including two pincer members that may be moved toward and away from each other and can be varied in length to accommodate different shaped work pieces.
U.S. Pat. No. 4,815,781 teaches an industrial robot hand including a fixed frame for connection to the end wrist portion of the arm of an industrial robot and a movable frame supported by the fixed frame and movable in a horizontal direction via guide rods. Pivotable plates are provided with engaging members along the movable frame to secure the material to be handled.
DE 42 38 101 A1 teaches a mechanism incorporating a steering arm having several hollow bars supporting a slide supporting a carriage, which slides on the bars. Clamping plates are located on the ends of the bars. The hollow bars accommodate pretensioned threaded rods. A piston rod is located centrally in the cage, and the stationary piston moves in a cylinder, associated with the slide. The hollow bars form pressure medium feeds to the cylinder.
It is, therefore, desirable to provide a more versatile EOAT for use with any product line.